1. Field of the Invention
The present invention relates to a medical tube for guiding a medical instrument inserted into a body cavity.
2. Description of the Related Art
In general, bloodless treatment for choledocholithiasis is performed by endoscopic transduodenal sphincterotomy is performed. However, there are not few cases of complication of choledocholithiasis and hepatolithiasis. In some case, treatment for hepatolithiasis is necessary even after removal of choledocholith by the endoscopic transduodenal sphincterotomy. Therefore, there is a demand for diagnosis of hepatholithiasis and bloodless treatment by peroral cholangioscopy.
However, when an endoscope representing a medial instrument inserted from the stomach side is set as a reference, the exit opening of a biliary tract is directed in a return direction with respect to a duodenum. Therefore, when it is attempted to insert the endoscope into the biliary tract, endoscope operation is difficult because it is necessary to insert the endoscope while bending a distal end of the endoscope to the back.
As a measure against this problem, for example, as disclosed in Japanese Examined Patent Application Publication No. 01-28581, there is known a technique for leading an endoscope into the biliary tract in a transpapillary manner using a flexible tubular member (an over tube).
A tubular member 101 disclosed in the document is shown in FIG. 41. As shown in the figure, when the peroral cholangioscopy is performed by using an endoscope, first, the tubular member 101 is inserted into an insertion portion of a not-shown endoscope for duodenum of a side-view type in advance. A distal end of the insertion portion of the endoscope projected from a distal end of this tubular member 101 is inserted to a papilla A (a duodenal papilla A) of a duodenum 104 in an observation direction. When the duodenal papilla A is confirmed by the endoscope for duodenum, the tubular member 101 is moved forward to bring a side hole 101a opened on the outer side of this tubular member 101 into a field of view of the endoscope for duodenum.
Thereafter, the endoscope for duodenum is pulled out and, instead, a cholangioscope 102 is inserted into this tubular member 101 and a distal end of an insertion portion 103 of this cholangioscope 102 is led to the side hole 101a. When the distal end of the insertion portion 103 is faced to the side hole 101a, the insertion portion 103 is bent and the distal end of the insertion portion 103 is inserted through the side hole 101a, led to the duodenal papilla A through this side hole 101a, and inserted into a choledoch B from this duodenal papilla A. An advancing direction of the insertion portion 103 of the cholangioscope 102 is led into the choledoch B with a distal end side edge P1 of this side hole 101a as a fulcrum.